1. Field of the Invention
The present invention relates to a rocker arm for an electric treadmill, and more particularly, to a device which adjusts to the curvature of the natural swing of the arms of the treadmill""s user and, therefore, makes a synchronic movement.
2. Description of the Prior Art
Many commercially available electric treadmills are provided with two rocker arms swingable backward and forward along with both arms of the operator and fitted to an upright frame, a base frame or a handrail. Even, a resistant element is added to the rocker arms so that the operator can exercise the arm muscle while walking. These disclosures can be seen in U.S. Pat. No. 5,460,586, 5,527,245, 5,688,209, 5,431,612, 5,207,622, 5,860,894, 5,709,632.
The rocker arms of the above-mentioned disclosures are swung in parabolic form since they are composed of a single element in combination with.a single pivotal point. This point is evidently contrary to the natural exercise mode of the human body so that the user feels uncomfortably during the exercise session when he holds the rocker arms.
It is a primary object of the present invention to remove the above-mentioned drawbacks and to provide a rocker arm for an electric treadmill whose movement path corresponds to the natural swing curvature of the user""s hands in order to reach the expected exercise effect.
It""s another object of the present invention to provide a rocker arm for an electric treadmill which is provided with a resistance element (e.g. balance weight, small-type hydraulic cylinder unit, etc.) in order to make full use of the rocker arms.